How realistic do you think that is, really? And what are you expecting to be ready when they ship it, functional hardware and not much on the software side?

That's a good question that I've been concerned about for a while. Currently hoping for best but planning for worse. Don't expect a lot of apps but hope for basic functionality and ability to run other Linux OS on it. The rest is gravy!

And what are you expecting to be ready when they ship it, functional hardware and not much on the software side?

For me, one of the big hopes is a fully-functional matrix client (specifically Fractal) from the start. The signs are good: http://danigm.net/fractal-hackfest2.html (note the links to Matrix and Purism near the end), and both Purism and Matrix have stated elsewhere that they are committed to this.

But what I don't get is why on earth do they decide to use latest kernel when test the HW?

I am pretty sure they had save some time use the "default" iMX kernel when test screen/touch an so on. That way they could faster verify hardware and ship the devkit faster and then the community could help port it the driver to the latest kernel version.

I doubt we will see the devkit before end of 2018. Probably we have to wait to Q1.

I am 100% sure they work as crazy to make it happen but since I also work with HW I know how much that can go wrong and make stuff delayed...

But using KiCad is also a bit of risky since they really have to make sure all footprints(kind of mecanicals parts) is correct. Some components in the Kicad default library is not...

But in the same time it could be worth it in the long run since the more company project designed in KiCad the better quality of the KiCad libraries and also better for hobbyist and small companies because they could hopefully throw Windows only program such as OrCad and Altium in the trashcan.

Usually there is big work to go next kernel , starting with the latest is good , although there is an addional " cost" , but it will pay back later.
Too many times products has been built with defacto kernel of time whic is actuallu already aged and when product is finally released, it's outdated.

The issue they have is to test hardware is working not test latest kernel now they do Both EG test unstsble/not ready driver in top of unstable hw. Now that not end user stuff. Its VERY lowleve÷ testomg now that is probably beter done with a know kernel IMHO.

Considering they've selected hardware specifically for mainline kernel support (no hacked together modules with custom requirements) , I can all but guarantee purism will use a recent kernel... in the 4.10 range. That is the entire point, after all.